CARTPT and leukemia: To investigate if pretreatment of leukemia cells with PipFcB may sensitize to CART-mediated lysis, CD19+ Daudi cells were incubated for 4 h, 8 h, or 12 h with different concentrations of PipFcB (10, 5 and 1 μM), and afterwards exposed to CARTs at different E:T ratios (20:1, 10:1, 5:1, 2.5:1, 1:1) for 4 h (Figure 3).